Apparatus and method for conditioning and monitoring media used for chemical-mechanical planarization

ABSTRACT

A method and apparatus for conditioning and monitoring a planarizing medium used for planarizing a microelectronic substrate. In one embodiment, the apparatus can include a conditioning body having a conditioning surface that engages a planarizing surface of the planarizing medium and is movable relative to the planarizing medium. A force sensor is coupled to the conditioning body to detect a frictional force imparted to the conditioning body by the planarizing medium when the conditioning body and the planarizing medium are moved relative to each other. The apparatus can further include a feedback device that controls the motion, position, or force between the conditioning body and the planarizing medium to control the conditioning of the planarizing medium.

TECHNICAL FIELD

[0001] The present invention relates to an apparatus and method forconditioning and monitoring media used for chemical-mechanicalplanarization of microelectronic substrates.

BACKGROUND OF THE INVENTION

[0002] Chemical-mechanical planarization (“CMP”) processes removematerial from the surface of a semiconductor wafer in the production ofintegrated circuits. FIG. 1 schematically illustrates a CMP machine 10having a platen 20. The platen 20 supports a planarizing medium 21 thatcan include a polishing pad 27 having a planarizing surface 29 on whicha planarizing liquid 28 is disposed. The polishing pad 27 may be aconventional polishing pad made from a continuous phase matrix material(e.g., polyurethane), or it may be a new generation fixed-abrasivepolishing pad made from abrasive particles fixedly dispersed in asuspension medium. The planarizing liquid 28 may be a conventional CMPslurry with abrasive particles and chemicals that remove material fromthe wafer, or the planarizing liquid may be a planarizing solutionwithout abrasive particles. In most CMP applications, conventional CMPslurries are used on conventional polishing pads, and planarizingsolutions without abrasive particles are used on fixed abrasivepolishing pads.

[0003] The CMP machine 10 also can include an underpad 25 attached to anupper surface 22 of the platen 20 and the lower surface of the polishingpad 27. A drive assembly 26 rotates the platen 20 (as indicated by arrowA), or it reciprocates the platen 20 back and forth (as indicated byarrow B). Because the polishing pad 27 is attached to the underpad 25,the polishing pad 27 moves with the platen 20.

[0004] A wafer carrier 30 positioned adjacent the polishing pad 27 has alower surface 32 to which a wafer 12 may be attached. Alternatively, thewafer 12 may be attached to a resilient pad 34 positioned between thewafer 12 and the lower surface 32. The wafer carrier 30 may be aweighted, free-floating wafer carrier, or an actuator assembly 40 may beattached to the wafer carrier to impart axial and/or rotational motion(as indicated by arrows C and D, respectively).

[0005] To planarize the wafer 12 with the CMP machine 10, the wafercarrier 30 presses the wafer 12 face-downward against the polishing pad27. While the face of the wafer 12 presses against the polishing pad 27,at least one of the platen 20 or the wafer carrier 30 moves relative tothe other to move the wafer 12 across the planarizing surface 29. As theface of the wafer 12 moves across the planarizing surface 29, materialis continuously removed from the face of the wafer 12.

[0006] One problem with CMP processing is that the throughput may drop,and the uniformity of the polished surface on the wafer may beinadequate, because waste particles from the wafer 12 accumulate on theplanarizing surface 29 of the polishing pad 27. The problem isparticularly acute when planarizing doped silicon oxide layers becausedoping softens silicon oxide and makes it slightly viscous as it isplanarized. As a result, accumulations of doped silicon oxide glaze theplanarizing surface 29 of the polishing pad 27 with a coating that cansubstantially reduce the polishing rate over the glazed regions.

[0007] To restore the planarizing characteristics of the polishing pads,the polishing pads are typically conditioned by removing theaccumulations of waste matter with an abrasive conditioning disk 50.Conventional abrasive conditioning disks are generally embedded withdiamond particles, and they are mounted to a separate actuator 55 on aCMP machine that can move the conditioning disk 50 rotationally,laterally, or axially, as indicated by arrows E, F, and G, respectively.Typical conditioning disks remove a thin layer of the pad materialitself in addition to the waste matter to form a new, clean planarizingsurface 29 on the polishing pad 27. Some conditioning processes alsoinclude disposing a liquid solution on the polishing pad 27 thatdissolves some of the waste matter as the abrasive disks abrade thepolishing surface.

[0008] One problem with conventional conditioning methods is that theconditioning disk 50 can lose effectiveness by wearing down or by havingthe interstices between abrasive particles plugged with particulatematter removed from the polishing pad 27. If the change in effectivenessis not detected, the polishing pad 27 may be insufficiently conditionedand subsequent planarizing operations may not remove a sufficientquantity of material from the wafer 12. Another problem is that theconditioning disk 50 may condition the polishing pad 27 in a nonuniformmanner, for example, because the build-up of deposits on the polishingpad may be non-uniform or because the relative velocity between thepolishing pad and the conditioning disk changes as the conditioning diskmoves radially across the planarizing surface 29.

[0009] One approach to addressing the above problems is to measure afriction force at an interface with the polishing pad. U.S. Pat. No.5,743,784 discloses detecting the roughness of a polishing pad with afloating head apparatus positioned away from the conditioning disk. Onedrawback with this method is that the friction force detected by thefloating head may not accurately represent the friction force betweenthe conditioning disk and the polishing pad. Furthermore, the separatefloating head adds to the overall complexity of the CMP apparatus.

[0010] Another approach is to measure a contact force between aconditioning end effector and the polishing pad, as disclosed in U.S.Pat. No. 5,456,627. As discussed above, a drawback with this approach isthat the contact force may not adequately represent the friction forcebetween the polishing pad and the conditioner.

[0011] U.S. Pat. No. 5,036,015 discloses sensing a change in frictionbetween the wafer and the polishing pad by measuring changes in currentsupplied to motors that rotate the wafer and/or the polishing pad todetect the endpoint of planarization. However, this method does notaddress the problem of detecting the condition of the conditioning disk.

SUMMARY OF THE INVENTION

[0012] The present invention is directed toward methods and apparatusesfor conditioning and monitoring a planarizing medium used forplanarizing a microelectronic substrate. In one aspect of the invention,the apparatus can include a conditioning body having a conditioningsurface configured to engage a planarizing surface of the planarizingmedium. In one embodiment (for example, when the planarizing mediumincludes a circular polishing pad, or an elongated polishing padextending between a supply roller and a take-up roller) the conditioningbody can have a circular planform shape. Alternatively, (for example,when the planarizing medium includes a high speed continuous looppolishing pad), the conditioning body can be elongated across a width ofthe polishing pad. At least one of the conditioning body and theplanarizing medium is movable relative to the other to condition theplanarizing surface.

[0013] The apparatus can further include a sensor coupled to theconditioning body to detect a frictional force imparted to theconditioning body by the planarizing medium when one of the conditioningbody and the planarizing medium moves relative to the other. The sensorcan be coupled to a support that supports the conditioning body relativeto the planarizing medium. For example, the support can include twosupport members, one pivotable relative to the other, and the sensor caninclude a force sensor positioned between the two support members todetect a force applied by one support member to the other as theconditioning body engages the planarizing medium. Alternatively, thesupport can include a piston movably received in a cylinder and thesensor can include a pressure transducer within the cylinder or apointer that detects motion of the piston relative to the cylinder.

[0014] In another aspect of the invention, the apparatus can include afeedback device that controls the relative velocity, position, or forcebetween the conditioning body and the planarizing medium in response toa signal received form the sensor. In still another aspect of theinvention, the conditioning body can be used to determine acharacteristic of the planarizing medium, and can further be used tocompare characteristics of one planarizing medium to characteristics ofanother.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a partially schematic, partial cross-sectional sideelevation view of a chemical mechanical planarizing apparatus inaccordance with the prior art.

[0016]FIG. 2 is a partially schematic, partial cross-sectional sideelevation view of an apparatus having a conditioning body and a pivotingsupport assembly in accordance with an embodiment of the invention.

[0017]FIG. 3 is a partially schematic, partial cross-sectional sideelevation view of an apparatus having a conditioning body supported by asupport assembly that includes a piston movably received in a cylinderin accordance with another embodiment of the invention.

[0018]FIG. 4 a partially schematic, partial cross-sectional sideelevation view of an apparatus having a conditioning body coupled to asupport assembly that includes a sensor positioned to detect linearmotion of the conditioning body in accordance with still anotherembodiment of the invention.

[0019]FIG. 5 is a partially schematic, partial cross-sectional sideelevation view of an apparatus having a conditioning body coupled to asupport assembly that includes a piston biased within a cylinder inaccordance with yet another embodiment of the invention.

[0020]FIG. 6 is a partially schematic, partial cross-sectional sideelevation view of an apparatus having a support assembly that includes astrain gauge in accordance with still another embodiment of theinvention.

[0021]FIG. 7 is a partially schematic, side elevation view of anapparatus having a conditioning body and a continuous polishing pad inaccordance with yet another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention is directed toward methods and apparatusesfor monitoring and conditioning planarizing media used for planarizing amicroelectronic substrate. The apparatus can include a conditioning bodyhaving a sensor that detects friction between the conditioning body andthe planarizing medium during conditioning. Many specific details ofcertain embodiments of the invention are set forth in the followingdescription and in FIGS. 2-7 to provide a thorough understanding of suchembodiments. One skilled in the art, however, will understand that thepresent invention may have additional embodiments and that they may bepracticed without several of the details described in the followingdescription.

[0023]FIG. 2 illustrates one embodiment of a CMP machine 110 inaccordance with the invention having a platen 120 and a planarizingmedium 121. In the embodiment shown in FIG. 2, the planarizing medium121 includes a polishing pad 127 releasably attached to the platen 120and a planarizing liquid 128 disposed on a planarizing surface 129 ofthe polishing pad 127. The platen 120 can be movable by means of aplaten drive assembly 126 that can impart rotational motion (indicatedby arrow A) and/or translational motion (indicated by arrow B) to theplaten 120. As was discussed above, the CMP machine 110 can also includea carrier 130 and a resilient pad 134 that together press amicroelectronic substrate 112 against the planarizing surface 129 of thepolishing pad 127. A carrier drive assembly 140 can be coupled to thecarrier 130 to move the carrier axially (indicated by arrow C) and/orrotationally (indicated by arrow D) relative to the platen 120.

[0024] The apparatus 110 can further include a conditioning body 150supported relative to the planarizing medium 121 by a support assembly160. The conditioning body 150 can have a generally circular planformshape and a conditioning surface 151 that can include abrasive particlessuch as diamonds or other relatively hard substances. In one embodiment,the conditioning body 150 can remain in a fixed position while theplanarizing medium 121 rotates and/or translates beneath theconditioning surface 151. In another embodiment, an actuator unit 190(shown schematically in FIG. 2) can move the conditioning body 150relative to the planarizing medium 121, as will be discussed in greaterdetail below.

[0025] The support assembly 160 can include an upright support 161coupled to the conditioning body 150 and a lateral support 162 coupledto the upright support 161. The upright support 161 can be coupled tothe conditioning body 150 at a gimbal joint 163 to allow theconditioning body 150 to rotate and pivot relative to the uprightsupport 161 during conditioning. The upright support 161 can be coupledto the lateral support 162 with a pivot pin 164 that allows the uprightsupport 161 to pivot relative to the lateral support 162. The lateralsupport 162 can include a forward portion 165 removably coupled to arear portion 166 with securing pins 167. Accordingly, the forwardportion 165 can be used to retrofit an existing rear portion 166.

[0026] In one embodiment, a force sensor 180 is positioned between theupright support 161 and the lateral support 162 to detect a compressiveforce transmitted from the upright support 161 to the lateral support162 when the conditioning body 150 and the planarizing medium 121 moverelative to each other. In one aspect of this embodiment, the forcesensor 180 can include an SLB series compression load cell availablefrom Transducer Techniques of Temeculah, Calif. In other embodiments,the force sensor 180 can include other devices, as will be discussed ingreater detail below.

[0027] In operation, the conditioning body 150 is positioned on theplaten 120, both to the left of center and forward of center as shown inFIG. 2. The platen 120 and the planarizing medium 121 rotate in thedirection indicated by arrow A, such that the portion of the planarizingmedium 121 in the foreground of FIG. 2 moves from right to left.Frictional forces between the planarizing medium 121 and theconditioning body 150 then impart a force on the conditioning body 150in the direction indicated by arrow H. Under the influence of the forceon the conditioning body 150, the upright support 161 tends to pivot ina clockwise direction about the pivot pin 164, compressing the forcesensor 180 between the upright support 161 and the lateral support 162.The force sensor 180 can detect the compressive force and can alsodetect changes in the compressive force resulting from changes in theplanarizing medium 121 and/or the conditioning body 150. For example,the frictional force between the planarizing medium 121 and theconditioning body 150 (and therefore the compressive force on the forcesensor 180) may increase as the conditioning body 150 removes materialfrom the planarizing surface 129 and roughens the planarizing surface.Conversely, the frictional force and the compressive force may decreaseas the conditioning surface 151 of the conditioning body 150 becomesglazed with material removed form the polishing pad 127 and/or theconditioning body 150.

[0028] In an alternate embodiment, for example, where the conditioningbody 150 contacts a portion of the planarizing medium 121 toward therear of FIG. 2, the planarizing medium 121 can impart a frictional forceon the conditioning body in a direction opposite that indicated by arrowH. Accordingly, the force sensor 180 can include a strain gauge or otherdevice configured to detect tensile (as opposed to compressive) forcesbetween the upright support 161 and the lateral support 162.

[0029] The actuator unit 190 can move the support assembly 160 and theconditioning body 150 relative to the planarizing medium 121, either inconjunction with or in lieu of moving the planarizing medium 121. In oneembodiment, the actuator unit 190 can include a controller 193 coupledto one or more actuators (shown schematically in FIG. 2) for movingand/or biasing the conditioning body 150. For example, the controller193 can be coupled to a lateral actuator 192 to move the supportassembly 160 and the conditioning body 150 laterally as indicated byarrow F, and a sweep actuator 195 to sweep the support assembly 160 andthe conditioning body 150 in a sweeping motion generally perpendicularto the plane of FIG. 2. The controller 193 can also be coupled to adownforce actuator 191 that can apply a downward force to the supportassembly 160 in the direction indicated by arrow G to vary the forcewith which the conditioning body 150 contacts the planarizing medium121.

[0030] Still further, the controller 193 can be coupled to a rotationalactuator 194 for rotating the conditioning body 150 relative to theplanarizing medium 121, as indicated by arrow E. In a further aspect ofthis embodiment, the force sensor 180 can be supplemented or replaced byan electrical current sensor 180 a coupled to the rotational actuator194. The current sensor 180 a can detect changes in the current drawn bythe rotational actuator 194 as the frictional forces between theconditioning body 150 and the planarizing medium 121 change.Alternatively, the current sensor 180 a can be supplemented or replacedby another type of sensor, such as a torque sensor, deflection sensor orstrain gauge, positioned in the drive train between the rotationalactuator 194 and the conditioning body 150 to measure forces on thedrive train caused by friction on the conditioning body 150.

[0031] In one embodiment, the force sensor 180 can be coupled to thecontroller 193 (as shown in dashed lines in FIG. 2) to provide afeedback loop for controlling the motion and/or downforce applied to theconditioning body 150 in response to changes detected by the forcesensor 180. For example, the controller 193 can include a mechanical ormicroprocessor feedback unit that receives signals from the force sensor180 and automatically controls the actuators, 191, 192, 194, and/or 195to control the position of the conditioning body 150, the speed withwhich the conditioning body 150 moves relative to the planarizing medium121, and/or the downforce between the conditioning body 150 and thepolishing pad 127. In a further aspect of this embodiment, thecontroller 193 can signal the user if changing any of the aboveparameters does not result in the desired change in frictional force.Accordingly, the controller 193 can prevent the conditioning body 150from applying an excessive force to the planarizing medium 121.

[0032] In an alternate embodiment, the force detected by the forcesensor 180 can be displayed to the user via a conventional displaydevice 196, such as a digital display, strip chart recorder, graphicdisplay or other type of display device. As the force sensor 180 detectsa change in the frictional force between the conditioning body 150 andthe planarizing medium 121, the user can clean or otherwise refurbishthe conditioning body 150 and/or manually increase the downforce on theconditioning body 150 to increase the rate with which the conditioningbody 150 conditions the planarizing medium 121.

[0033] The apparatus 110 can be operated according to one or more ofseveral methods. For example, the force sensor 180 can monitor thefrictional force between the conditioning body 150 and the planarizingmedium 121 during in situ conditioning (which is simultaneous withplanarizing the wafer 112) or ex situ conditioning (which is conductedseparately from planarization). The controller 193 can adjust thedownforce on the conditioning body, in response to signals received fromthe force sensor 180, to keep the frictional force between theconditioning body 150 and the planarizing medium 121 approximatelyconstant. For example, the frictional force can be a function of thesurface characteristics of the planarizing surface 129 and/or theconditioning surface 151, the normal force between the two surfaces, andthe relative velocity between the two surfaces. The relative velocitybetween the two surfaces can in turn be a function of the rotationaland/or translational speed of the polishing pad 127, the rotationaland/or translational speed of the conditioning body 150, and theposition of the conditioning body 150 relative to the polishing pad 127.When the relative velocity is low, the frictional forces tend to be low.As the relative velocity increases, the frictional forces tend toincrease until, at some point, the conditioning body 150 can “plane” onthe planarizing liquid 128, which reduces the frictional force.Accordingly, one method of operation can include selecting a targetfrictional force and adjusting the rotation speed of the platen 120 tokeep the actual frictional force approximately the same as the targetfrictional force. In other embodiments, other variables affecting thefrictional force can be controlled, either manually or automatically viathe controller 193, to keep the frictional force approximately constant.

[0034] In another method of operation, the force sensor 180 can be usedto monitor the condition of the polishing pad 127. For example, arelatively light downforce can be applied to the conditioning body 150,generating a small frictional force between the conditioning body 150and the polishing pad 127. The small frictional force can be either theweight of the conditioning body 150 or the weight combined with adownforce applied to the conditioning body 150 with the downforceactuator 191. During planarization, the frictional force can change(either upwardly or downwardly, depending on the characteristics of thepolishing pad 127 and the type of material removed from the substrate112), indicating a change in the effectiveness with which the polishingpad 127 planarizes the substrate 112. The force sensor 180 can detectthis change and indicate to the user when the efficiency of thepolishing pad 127 is less than optimal. In a further aspect of thisembodiment, the controller 193 can increase the downforce on theconditioning body 150 upon detecting the change in characteristics ofthe polishing pad 127, and thereby condition the polishing pad 127 byremoving material from the planarizing surface 129.

[0035] In still another method of operation, the rotational speed of thepolishing pad 127 can be varied based on the position of theconditioning body 150 to maintain the relative linear velocity betweenthe two approximately constant. For example, the rotational speed of thepolishing pad 127 can decrease as the conditioning body 150 moves towardthe periphery of the polishing pad 127 and can increase as theconditioning body 150 moves toward the center of the polishing pad 127.Accordingly, the downforce applied to the conditioning body 150 need notbe adjusted as the conditioning body 150 moves relative to the polishingpad 127, except to account for changes in the surface conditions of theconditioning body 150 and the polishing pad 127.

[0036] In yet another method of operation, the apparatus 110 can be usedto compare two or more polishing pads 127. For example, a selecteddownforce can be applied to the conditioning body 150 while theconditioning body engages a first polishing pad 127. The resultingfrictional force, as measured by the force sensor 180 can be comparedwith the frictional force obtained when the conditioning body 150engages a second polishing pad (not shown).

[0037] An advantage of the apparatus shown in FIG. 2 is that the forcesensor 180 can detect changes in the performance of the conditioningbody 150 as the conditioning body 150 conditions the polishing pad 127.The user can respond to the detected changes by adjusting the speed,position or surface characteristics of the conditioning body 150 toincrease the operating efficiency of the conditioning body. A furtheradvantage is that the force sensor 180 can be coupled to the controller193 in a feedback loop to automatically adjust the performance of theconditioning body 150 by controlling the operation of one or more of theactuators 191, 192, 194, and 195. Accordingly, the speed, positionand/or surface characteristics of the conditioning body 150 can beadjusted on a continuous or intermittent basis to uniformly conditionthe polishing pad 127.

[0038] Still a further advantage of the apparatus 110 is that the forcesensor 180 can directly and therefore more accurately detect changes inthe characteristics of the conditioning body 150. This arrangement isunlike some conventional arrangements in which a device separate fromthe conditioning body contacts the polishing pad 127 and detects a forcewhich may or may not represent the forces on the conditioning body 150.

[0039] Yet another advantage is that the force sensor 180 can be used todetect changes in the roughness of the polishing pad 127. Accordingly,the apparatus 110 can be used to determine when the polishing pad 127has been adequately conditioned, for example, when the frictional forcebetween the polishing pad 127 and the conditioning body 150 exceeds aselected threshold value. Furthermore, the force sensor 180 can detectroughness variations across the planarizing surface 129 of the polishingpad 127 as the conditioning body is moved over the planarizing surface129. For example, when the platen 20 rotates in the direction indicatedby arrow A, the relative velocity between the conditioning body 150 andthe polishing pad 127 will be higher toward the periphery of thepolishing pad 127 then toward the center of the polishing pad, resultingin radial non-uniformities in the roughness of the planarizing surface129. As discussed above, the actuators 191, 192, 194, and 195 can thenbe controlled by the controller 193 to reduce the roughness variationsacross the planarizing surface 129.

[0040]FIG. 3 is a partially schematic, partial cross-sectional sideelevation view of an apparatus 210 in accordance with another embodimentof the invention. The apparatus includes a conditioning body 250positioned adjacent the planarizing medium 121 in a manner generallysimilar to that discussed above with reference to FIG. 2. Theconditioning body 250 is coupled to a support assembly 260 having anupright support 261 coupled at one end to the conditioning body 250 andcoupled at the other end to a lateral support 262. As shown in FIG. 3,the lateral support 262 can include an open-ended cylinder portion 269sized to slidably receive a corresponding piston portion 268 of theupright support 261.

[0041] In one embodiment, both the cylinder portion 269 and the pistonportion 268 can have generally circular cross-sectional shapes and inother embodiments, both portions can have square or othercross-sectional shapes. In any case, a seal 271 can be positionedbetween the piston portion 268 and the walls of the cylinder portion 269to seal the interface therebetween while allowing the piston portion 268to slide relative to the cylinder portion 269. Accordingly, the pistonportion 268 can slide slightly further into the cylinder portion 269 asthe frictional force between the planarizing medium 121 and theconditioning body increases, and can slide slightly out of the cylinderportion 269 as the frictional force decreases.

[0042] A force sensor 280, such as a pressure transducer, can bepositioned within the cylinder portion to detect changes in pressurewithin the cylinder portion 269 as the piston portion 268 moves relativeto the cylinder portion under the force imparted to it by theconditioning body 250. In one aspect of this embodiment, the cylinderportion 269 can include an air supply conduit 270 that introduces asmall amount of air through an inlet opening 272 in a wall of thecylinder portion 269. The air can entrain particulates within thecylinder portion 269 and purge them through an outlet opening 273. In afurther aspect of this embodiment, the inlet opening 272 and the outletopening 273 are sized such that the flow of air through the cylinderportion 269 does not adversely affect the measurements of the forcesensor 280. Alternatively, the inlet opening 272, the outlet opening 273and the conduit 270 can be eliminated.

[0043] An advantage of the apparatus 210 shown in FIG. 3 is that theforce sensor 280 can detect changes in the frictional force between theconditioning body 250 and the planarizing medium 121 as the pistonportion 268 moves both into and out of the cylinder portion 269.Accordingly, a single force sensor 280 can detect both increases anddecreases in the frictional force between the conditioning body 250 andthe planarizing medium 121. Alternatively, the single force sensor 280can detect changes in the frictional force if the platen rotates eitherin the direction indicated by arrow A, or the opposite direction.Another advantage is that the environment within which the force sensor280 operates can either be sealed or purged to reduce the likelihood forcontamination of the force sensor 280, improving the reliability ofmeasurements made by the force sensor.

[0044]FIG. 4 is a partially schematic, partial cross-sectional sideelevation view of an apparatus 310 in accordance with another embodimentof the invention. The apparatus 310 includes a conditioning body 350coupled to a support assembly 360 in a manner generally similar to thatdiscussed above with reference to FIG. 3. The support assembly 360includes an upright support 361 having a piston portion 368 that issealably and slidably received in a corresponding cylinder portion 369of a lateral support 362. In one aspect of this embodiment, theapparatus 310 can have a sensor 380 a that includes a pointer 381coupled to the lateral support 362 and a scale 382 on the uprightsupport 361. As the frictional forces between the conditioning body 350and the planarizing medium 121 change, the upright support 361 tends tomove relative to the lateral support 362. The relative motion betweenthe upright support 361 and the lateral support 362 can be detectedvisually by observing the relative motion between the pointer 381 andthe scale 382.

[0045] In another embodiment, the force sensor 380 a can be supplementedby or replaced by a force sensor 380 b that includes a lineardisplacement transducer. For example, in one aspect of this embodiment,the linear displacement transducer 380 b can include a magnet in one orthe other of the piston portion 368 and the cylinder portion 369 and amagnetic field detector in the other portion. In other embodiments, thelinear displacement transducer 380 b can include other devices. In anycase, the linear displacement transducer 380 b can generate anelectrical signal that is transmitted to the controller 193 in a mannergenerally similar to that discussed above with reference to FIG. 2. Thecontroller 193 can in turn transmit signals to the actuators 191, 192and 195, also in a manner generally similar to that discussed above withreference to FIG. 2 (for purposes of illustration, the rotationalactuator 194 shown in FIG. 2 is not shown in FIG. 4). An advantage ofthe apparatus 310 shown in FIG. 4 is that it can provide a mechanicalvisual indicator of the frictional force between the conditioning body350 and the planarizing medium 121, in addition to or in lieu of adigital signal for controlling the motion of the conditioning body 350.

[0046] As shown in FIG. 4, the piston portion 368 is sealably engagedwithin the cylinder portion 369 so that a cushion of air within thecylinder portion 369 resists axial motion of the piston portion 368. Inanother embodiment, shown in partial cross-sectional elevation view inFIG. 5, the resistance can be provided by a spring 374 positionedbetween the piston portion 368 and an end wall of the cylinder portion369. The spring 374 can resist motion of the piston portion 368 intoand/or out of the cylinder portion 369. Accordingly, the piston portion368 need not be sealably engaged with the cylinder portion 369. In oneaspect of the embodiment, one or more bearings 375 can be positionedbetween the cylinder portion 369 and the piston portion 368 to ensurethat the piston portion moves smoothly and axially relative to thecylinder portion 369.

[0047]FIG. 6 is a partially schematic, partial cross-sectional sideelevation view of an apparatus 410 having a support member 460 with astrain gauge 480 attached thereto in accordance with another embodimentof the invention. In one aspect of this embodiment, the support member460 can include a single piece that extends from the actuator unit 190to the conditioning body 350. The support member 460 can be generallyrigid, but can also flex by a measurable amount as the frictional forcesbetween the conditioning body 150 and the planarizing medium 121 change.The strain gauge 480 can be attached to the support member 460 at anysuitable location where it can detect deflections of the support member.

[0048] In the embodiment shown in FIG. 6, the apparatus 410 includes asingle strain gauge 480 and in other embodiments, the apparatus 410 caninclude a plurality of strain gauges to detect deflections of thesupport member 450 along one or more axes. In any case, the straingauge(s) 480 can be coupled to the display device 196 to provide theuser with a visual indication of the changes in frictional forcesbetween the conditioning body 350 and the planarizing medium 121, and/orthe strain gauge(s) 480 can be coupled to the controller 193 toautomatically control the conditioning body 350 in response to thechanges in frictional force. An advantage of the apparatus 410 shown inFIG. 6 is that it can include fewer moving parts than other apparatusesand may therefore be easier and less expensive to build and maintain.

[0049]FIG. 7 is a partially schematic, side elevation view of anapparatus 510 having two rollers 525 and a continuous polishing pad 527extending around the two rollers 525. The polishing pad 527 has aplanarizing surface 529 facing outwardly from the rollers 525 and can besupported by a continuous support band 525, formed from a flexiblematerial, such as a thin sheet of stainless steel. A pair of platens 520provide additional support for the polishing pad 527 at two opposingplanarizing stations. Two carriers 530 aligned with the platens 520 atthe planarizing stations can each bias a substrate 112 against opposingoutwardly facing portions of the polishing pad 527. Devices having thefeatures discussed above with reference to FIG. 7 are available fromAplex, Inc. of Sunnyvale, Calif. under the name AVERA™. Similar deviceswith a horizontally oriented polishing pad 527 and a single carrier 530are available from Lam Research Corp. of Fremont, Calif.

[0050] The apparatus 510 can further include a conditioning body 550supported relative to the polishing pad 527 by a support assembly 560.The conditioning body 550 can have an abrasive conditioning surface 551pressed against the polishing pad 527 to condition the polishing pad527. In one embodiment, the conditioning body 550 can be elongated in aplane transverse to the plane of FIG. 7 to span the entire width of thepolishing pad 527. In one aspect of this embodiment, the conditioningbody 550 can be generally rigid in a direction normal to the polishingpad 527 so that a normal force applied to one portion of theconditioning body 550 is distributed over the width of the conditioningbody 550. Alternatively, the conditioning body 550 can be compliant inthe normal direction to isolate the normal forces applied to differentportions of the conditioning body 550, as will be discussed in greaterdetail below.

[0051] The support assembly 560 presses the conditioning body 550against the polishing pad 527 and can include a first support member 561coupled to the conditioning body 550 and a second support member 562coupled to the first support member 561. The first support member 561can be rigidly coupled to the conditioning body 550 or, alternatively,the first support member 561 can be coupled to the conditioning body 550with a gimbal joint 563, as was discussed above with reference to FIG.2. The first support member 561 can be coupled to the second supportmember 562 with a pivot pin 564 that allows the first support member 561to pivot relative to the second support member 562 in a manner similarto that discussed above with reference to FIG. 2.

[0052] In one embodiment, a pair of force sensors 580 are positioned onopposite sides of the first support member 561 between the first supportmember 561 and the second support member 562 to detect forcestransmitted from the first support member 561 to the second supportmember 562 when the polishing pad 527 moves relative to the conditioningbody 550. Alternatively, the force sensors 580 can be positioned onother portions of the support assembly 560 or the conditioning body 550,so long as they are configured to detect the frictional forces betweenthe conditioning body 550 and the polishing pad 527.

[0053] The apparatus 510 can also include an actuator unit 590 to applyforces to the conditioning body 550. For example, the actuator unit 590can include a controller 593 coupled to a normal force actuator 591 toapply a force to the support assembly 560 that is normal to thepolishing pad 527. Accordingly, the actuator unit 590 can vary the forcewith which the conditioning body 550 engages with the polishing pad 527.As was discussed above with reference to FIG. 2, the controller 593 canbe coupled to the sensors 580 to change the normal force applied to theconditioning body 550 in response to signals received from the forcesensors 580.

[0054] In one embodiment (for example, when the conditioning body 550 isgenerally rigid), the support assembly 560 can engage the conditioningbody 550 midway across the span of the conditioning body 550 to apply anapproximately uniform normal force across the width of the polishing pad527. Alternatively, a plurality of support assemblies 560 can be coupledacross the span of the conditioning body 550 to apply constant orvariable forces to the conditioning body 550. For example, when theconditioning body 550 is compliant in the normal direction, each of theplurality of support assemblies 560 can independently control the normalforce applied to a spanwise portion of the conditioning body 550. Anadvantage of this arrangement is that the normal force applied to theconditioning body 550 can be locally increased to account for localvariations in the characteristics of the polishing pad 527 and/or theconditioning surface 551 of the conditioning body 550.

[0055] During operation, the continuous polishing pad 527 moves at arelatively high speed around the rollers 525 while the carriers 530press the substrates 112 against the polishing pad 527. An abrasiveslurry or other planarizing liquid having a suspension of abrasiveparticles is introduced to the surface of the polishing pad 527 which,in combination with the motion of the polishing pad 527 relative to thesubstrates 112, mechanically removes material from the substrates 112.The polishing pad 527 can be conditioned before, after, or duringplanarization with the conditioning body 550 by pressing theconditioning body against the polishing pad 527, in a manner generallysimilar to that discussed above with reference to FIGS. 2 and 7.

[0056] From the foregoing it will be appreciated that, although specificembodiments of the invention have been described herein for purposes ofillustration, various modifications may be made without deviating fromthe spirit and scope of the invention. For example, the force sensor andconditioning bodies can be used in conjunction with rotary planarizingdevices and continuous polishing pad devices, as shown in the figures,and can also be used with web-format planarizing devices in which theplanarizing medium is scrolled across the platen from a supply roller toa take-up roller and the conditioner moves relative to the planarizingmedium to condition the planarizing medium in a manner generally similarto that discussed above with reference to FIG. 2. Accordingly, theinvention is not limited except as by the appended claims.

1. An apparatus for monitoring conditioning of a planarizing medium usedfor planarizing a microelectronic substrate, comprising: a conditioningbody having a conditioning surface configured to engage a planarizingsurface of the planarizing medium, at least one of the conditioning bodyand the planarizing medium being movable relative to the other of theconditioning body and the planarizing medium to condition theplanarizing surface; and a sensor coupled to the conditioning body todetect a frictional force in a plane of the planarizing surface, thefrictional force being imparted to the conditioning body by theplanarizing medium when the one of the conditioning body and theplanarizing medium is moved relative to the other of the conditioningbody and the planarizing medium.
 2. The apparatus of claim 1 wherein theplanarizing medium includes a polishing pad.
 3. The apparatus of claim 1wherein the conditioning body has a conditioning surface generallyparallel to the planarizing surface.
 4. The apparatus of claim 1 whereinthe conditioning body includes abrasive elements for abrading theplanarizing surface of the planarizing medium.
 5. The apparatus of claim1 , further comprising a support member coupled to the conditioningbody, further wherein the sensor includes a strain gauge connected tothe support member to detect a deflection of the support memberresulting from the force on the conditioning body.
 6. The apparatus ofclaim 1 , further comprising: a first support member having first andsecond ends and being rotatably coupled toward the first end to theconditioning body, the second end of the first support member extendingaway from the conditioning body; and a second support member coupled ata pivotable coupling to the first support member toward the second endof the first support member, the sensor being positioned between thefirst and second support members, the first support member beingpivotable relative to the second support member to transmit a force tothe sensor corresponding to the frictional force.
 7. The apparatus ofclaim 1 wherein the sensor includes a force sensor.
 8. The apparatus ofclaim 1 wherein the sensor includes a strain gauge.
 9. The apparatus ofclaim 1 , further comprising an electric actuator coupled to theconditioning body to rotate the conditioning body relative to thepolishing pad, wherein the sensor includes a current sensor coupled tothe actuator to detect an electric current drawn by the actuator. 10.The apparatus of claim 1 , further comprising an actuator coupled to theconditioning body for controlling at least one of a position of theconditioning body and an approximately normal force between theconditioning body and the planarizing medium, the actuator being coupledto the sensor to receive signals from the sensor and adjust the one ofthe position and the approximately normal force in response to thesignal.
 11. The apparatus of claim 1 , further comprising: a piston; anda cylinder having an open end and a closed end, the cylinder sealablyand slidably receiving the piston, at least one of the piston and thecylinder being coupled to the conditioning body to slide relative to theother of the piston and the cylinder under the influence of thefrictional force on the conditioning body, the piston and the cylinderdefining a sealed gap between an end of the piston and the closed end ofthe cylinder, the sensor being positioned within the gap for measuring achange in pressure within the gap as the piston moves relative to thecylinder.
 12. The apparatus of claim 11 wherein the piston has agenerally circular cross-sectional shape and the cylinder has anaperture with a generally circular cross-sectional shape for receivingthe piston.
 13. The apparatus of claim 11 wherein the piston has agenerally rectangular cross-sectional shape and the cylinder has anaperture with a generally rectangular cross-sectional shape forreceiving the piston.
 14. The apparatus of claim 1 , further comprising:a piston; and a cylinder having an open end and a closed end, thecylinder slidably receiving the piston, at least one of the piston andthe cylinder being coupled to the conditioning body to slide relative tothe other of the piston and the cylinder under the influence of thefrictional force on the conditioning body, the piston and the cylinderdefining a gap between an end of the piston and the closed end of thecylinder, the sensor including a gauge positioned to measure movement ofthe one of the piston and the cylinder relative to the other of thepiston and the cylinder.
 15. The apparatus of claim 14 wherein thepiston is sealably engaged with the cylinder.
 16. The apparatus of claim14 , further comprising a biasing member coupled to the cylinder and thepiston to bias the piston toward or away from the cylinder.
 17. Theapparatus of claim 14 wherein the gauge includes a pointer on one of thepiston and the cylinder and a scale on the other of the piston and thecylinder, the pointer being aligned with the scale and movable relativeto the scale to indicate relative movement between the piston and thecylinder.
 18. The apparatus of claim 1 wherein the planarizing mediumincludes a polishing pad elongated to form a continuous loop extendingover at least two rollers, further wherein the conditioning body extendstransverse to the polishing pad.
 19. The apparatus of claim 18 whereinthe conditioning body is generally rigid, further comprising an actuatorcoupled to the conditioning body to control a force between theconditioning body and the polishing pad.
 20. The apparatus of claim 18wherein the conditioning body is at least partially compliant in adirection approximately normal to the polishing pad, further comprisinga plurality of actuators coupled to the conditioning body, each actuatorconfigured to control a normal force between the polishing pad and aportion of the conditioning body.
 21. The apparatus of claim 1 whereinthe conditioning body has a generally circular planform shape.
 22. Anapparatus for measuring forces during conditioning of achemical-mechanical planarizing surface, comprising: a planarizingmedium having a planarizing surface for removing material from amicroelectronic substrate, the planarizing surface defining aplanarizing surface plane; a conditioning body adjacent to theplanarizing medium, at least one of the conditioning body and theplanarizing medium being movable relative to the other of theconditioning body and the planarizing medium for conditioning theplanarizing surface, the conditioning body and the planarizing mediumgenerating a force in the planarizing surface plane when the one of theconditioning body and the planarizing medium moves relative to the otherof the conditioning body and the planarizing medium; and a sensoroperatively coupled to the conditioning body to detect the force. 23.The apparatus of claim 22 wherein the planarizing medium includes apolishing pad.
 24. The apparatus of claim 22 wherein the conditioningbody has a conditioning surface generally parallel to the planarizingsurface.
 25. The apparatus of claim 22 wherein the conditioning body isrotatable relative to the planarizing medium.
 26. The apparatus of claim22 wherein the conditioning body is translatable relative to theplanarizing medium.
 27. The apparatus of claim 22 wherein theplanarizing medium is rotatable relative to the conditioning body. 28.The apparatus of claim 22 wherein the force is a drag force, furthercomprising: a first support member having first and second ends andbeing rotatably coupled toward the first end to the conditioning body,the second end of the first support member extending away from theconditioning body; and a second support member coupled at a pivotablecoupling to the first support member toward the second end of the firstsupport member, the sensor being positioned between the first and secondsupport members, the first support member being pivotable relative tothe second support member to transmit a force to the sensorcorresponding to the drag force.
 29. The apparatus of claim 22 whereinthe sensor includes a force sensor.
 30. The apparatus of claim 22wherein the sensor includes a strain gauge.
 31. The apparatus of claim22 , further comprising: a piston; and a cylinder having an open end anda closed end, the cylinder slidably receiving the piston, at least oneof the piston and the cylinder being coupled to the conditioning body toslide relative to the other of the piston and the cylinder under theinfluence of the force on the conditioning body, the piston and thecylinder defining a gap between an end of the piston and the closed endof the cylinder, the force sensor including a gauge positioned tomeasure movement of the piston relative to the cylinder.
 32. Theapparatus of claim 31 wherein the piston is sealably engaged with thecylinder.
 33. The apparatus of claim 31 , further comprising a biasingmember coupled to the cylinder and the piston to bias the piston towardor away from the cylinder.
 34. The apparatus of claim 22 , furthercomprising a feedback device coupled to the sensor and the conditioningbody for changing at least one of the force between the conditioningbody and the polishing pad and a position of the conditioning bodyrelative to the polishing pad in response to a signal from the sensor.35. An apparatus for monitoring conditioning of a planarizing mediumused for chemical-mechanical planarization of a microelectronicsubstrate, comprising: a conditioning body having a conditioning surfaceconfigured to engage a planarizing surface of the planarizing medium, atleast one of the conditioning body and the planarizing medium beingmovable relative to the other of the conditioning body and theplanarizing medium to condition the planarizing surface, theconditioning body generating a drag force generally parallel to theplanarizing surface; an actuator coupled to the conditioning body with asupport assembly to control at least one of a generally normal forcebetween the conditioning body and the planarizing medium and a positionof the conditioning body relative to the planarizing medium; a sensorcoupled to the support assembly to detect the drag force; and a feedbackdevice coupled to the actuator to control activation of the actuator inresponse to a signal received from the force sensor.
 36. The apparatusof claim 35 wherein the feedback device includes a microprocessor. 37.The apparatus of claim 35 wherein the actuator is positioned to move theconditioning body laterally over the planarizing surface.
 38. Theapparatus of claim 35 wherein the actuator is positioned to rotate theconditioning body in a generally circular motion over the planarizingsurface.
 39. The apparatus of claim 35 wherein the planarizing mediumincludes a polishing pad.
 40. The apparatus of claim 35 , furthercomprising: a first support member having first and second ends andbeing rotatably coupled toward the first end to the conditioning body,the second end of the first support member extending away from theconditioning body; and a second support member coupled at a pivotablecoupling to the first support member toward the second end of the firstsupport member, the sensor being positioned between the first and secondsupport members, the first support member being pivotable relative tothe second support member to transmit a force to the sensorcorresponding to the drag force.
 41. The apparatus of claim 35 whereinthe sensor includes a force sensor.
 42. The apparatus of claim 35wherein the sensor includes a strain gauge.
 43. The apparatus of claim35 , further comprising: a piston; and a cylinder having an open end anda closed end, the cylinder slidably receiving the piston, at least oneof the piston and the cylinder being coupled to the conditioning body toslide relative to the other of the piston and the cylinder under theinfluence of the force on the conditioning body, the piston and thecylinder defining a gap between an end of the piston and the closed endof the cylinder, the sensor being positioned to detect relative motionbetween the piston and the cylinder.
 44. The apparatus of claim 43wherein the piston is sealably engaged with the cylinder and the sensorincludes a pressure gauge positioned within the gap to detect a changein pressure in the gap when one of the piston and the cylinder movesrelative to the other.
 45. The apparatus of claim 43 , furthercomprising a biasing member coupled to the cylinder and the piston tobias the piston toward or away from the cylinder.
 46. A method formonitoring conditioning of a planarizing medium used for planarizing amicroelectronic substrate, comprising: moving at least one of theplanarizing medium and a conditioning body relative to the other of theplanarizing medium and the conditioning body while the conditioning bodyis engaged with a planarizing surface of the planarizing medium; andmonitoring the conditioning body to detect a force of the planarizingmedium on the conditioning body.
 47. The method of claim 46 whereinmonitoring the conditioning body includes detecting a frictional forceon the conditioning body in a plane generally parallel to a plane of theplanarizing surface.
 48. The method of claim 46 wherein moving at leastone of the conditioning body and the planarizing medium includesrotating the conditioning body relative to the planarizing medium withan electric motor, further wherein detecting the force includesdetecting an electrical current drawn by the motor.
 49. The method ofclaim 46 wherein moving at least one of the conditioning body and theplanarizing medium includes rotating the planarizing medium relative tothe conditioning body.
 50. The method of claim 46 wherein theconditioning body is coupled to a support member for supporting theconditioning body relative to the planarizing medium, further whereinmonitoring the conditioning body includes measuring a force transmittedto the support member by the conditioning body.
 51. The method of claim50 wherein the support member includes a generally upwardly extendingportion coupled to the conditioning body and a generally laterallyextending portion pivotably coupled to the upwardly extending portion,further wherein monitoring the conditioning body includes detecting aforce between the upwardly extending portion and the laterally extendingportion with a force sensor.
 52. The method of claim 50 whereinmonitoring the conditioning body includes detecting a deflection of thesupport member.
 53. The method of claim 50 wherein the support memberincludes a piston slidably received in a cylinder and monitoring theconditioning body includes detecting a movement of one of the piston andthe cylinder relative to the other of the piston and the cylinder. 54.The method of claim 53 , further comprising biasing one of the pistonand the cylinder toward or away from the other of the piston and thecylinder.
 55. The method of claim 50 wherein the support member includesa piston slidably and sealably received in a cylinder to form a sealedspace between an end of the cylinder and an end of the piston, furtherwherein monitoring the conditioning body includes detecting a pressurewithin the sealed space.
 56. The method of claim 46 wherein moving atleast one of the conditioning body and the planarizing medium relativeto the other of the conditioning body and the planarizing mediumincludes sweeping the conditioning body laterally over the planarizingsurface of the planarizing medium while rotating the planarizing mediumrelative to the conditioning body.
 57. The method of claim 46 , furthercomprising removing material from the planarizing medium while at leastone of the conditioning body and the planarizing medium moves relativeto the other of the conditioning body and the planarizing medium. 58.The method of claim 46 , further comprising adjusting a force applied tothe conditioning body approximately normal to the planarizing surface inresponse to detecting a force of the planarizing medium on theconditioning body.
 59. The method of claim 46 wherein moving at leastone of the planarizing medium and the conditioning body includesrotating the planarizing medium at a variable rate as the conditioningbody moves across the planarizing medium to maintain a relative velocitybetween the planarizing medium and the conditioning body at anapproximately constant value.
 60. A method for monitoring conditioningof a planarizing medium used for planarizing a microelectronicsubstrate, the method comprising: coupling a sensor to a conditioningbody; engaging the conditioning body with the planarizing medium andmoving at least one of the conditioning body and the planarizing mediumrelative to the other of the conditioning body and the planarizingmedium while the conditioning body engages the planarizing medium; andmonitoring the conditioning body to detect a frictional force betweenthe conditioning body and the planarizing medium.
 61. The method ofclaim 60 wherein moving at least one of the conditioning body and theplanarizing medium includes rotating the conditioning body relative tothe planarizing medium with an electric motor, further wherein detectingthe frictional force includes detecting an electric current drawn by themotor.
 62. The method of claim 60 wherein the conditioning body iscoupled to a support member for supporting the conditioning bodyrelative to the planarizing medium, further wherein monitoring theconditioning body includes measuring a force transmitted to the supportmember by the conditioning body.
 63. The method of claim 62 whereinmonitoring the conditioning body includes detecting a deflection of thesupport member.
 64. The method of claim 62 wherein the support memberincludes a piston slidably received in a cylinder and monitoring theconditioning body includes detecting a movement of one of the piston andthe cylinder relative to the other of the piston and the cylinder. 65.The method of claim 62 wherein the support member includes a pistonslidably and sealably received in a cylinder to form a sealed spacebetween an end of the cylinder and an end of the piston, further whereinmonitoring the conditioning body includes detecting a pressure withinthe sealed space.
 66. The method of claim 60 wherein the planarizingmedium includes a polishing pad and moving at least one of theplanarizing medium and the conditioning body relative to the other ofthe planarizing medium and the conditioning body includes rotating thepolishing pad relative to the conditioning body.
 67. A method forcontrolling conditioning of a planarizing medium used for planarizing amicroelectronic substrate, the method comprising: engaging aconditioning body with the planarizing medium and moving at least one ofthe conditioning body and the planarizing medium relative to the otherof the conditioning body and the planarizing medium while theconditioning body engages the planarizing medium; detecting a frictionalforce between the conditioning body and the planarizing medium; andcontrolling at least one of a force between the conditioning body andthe planarizing medium and a speed of the conditioning body relative tothe planarizing medium in response to detecting the frictional forcebetween the conditioning body and the planarizing medium.
 68. The methodof claim 67 wherein controlling a force between the conditioning bodyand the planarizing medium includes receiving a force signal from aforce sensor and transmitting a command signal to an actuator coupled tothe conditioning body.
 69. The method of claim 68 wherein receiving theforce signal includes receiving the force signal with a microprocessorand transmitting a command signal includes transmitting the commandsignal from the microprocessor.
 70. The method of claim 67 whereincontrolling a force includes adjusting a force on the conditioning bodythat is approximately normal to a planarizing surface of the planarizingmedium.
 71. The method of claim 67 wherein the planarizing mediumincludes a polishing pad and moving at least one of the conditioningbody and the planarizing medium relative to the other of theconditioning body and the planarizing medium includes rotating thepolishing pad relative to the conditioning body.
 72. The method of claim67 wherein controlling a speed of the conditioning body relative to theplanarizing medium includes moving the conditioning body radiallyrelative to the planarizing medium.
 73. The method of claim 68 whereincontrolling a speed of the conditioning body includes rotating at leastone of the conditioning body and the planarizing medium relative to theother about an axis generally normal to the planarizing medium.
 74. Amethod for monitoring a polishing pad used for planarizing amicroelectronic substrate, the method comprising: engaging aconditioning body with a planarizing surface of the polishing pad;applying a force to the polishing pad via the conditioning body; movingat least one of the polishing pad and the conditioning body relative tothe other of the polishing pad and the conditioning body; and detectinga frictional force of the polishing pad on the conditioning body in aplane of the planarizing surface.
 75. The method of claim 74 whereinapplying a force includes applying a force to the conditioning bodydifferent than a weight of the conditioning body.
 76. The method ofclaim 74 wherein the force is a first force, further comprisingconditioning the polishing pad by applying a second force to theconditioner greater than the first force to remove material from theplanarizing surface of the polishing pad.
 77. The method of claim 74wherein the polishing pad is a first polishing pad and the frictionalforce is a first frictional force, further comprising: applying a forceto a second polishing pad via the conditioning body; moving at least oneof the second polishing pad and the conditioning body relative to theother of the second polishing pad and the conditioning body; detecting asecond frictional force of the second polishing pad on the conditioningbody in a plane of the planarizing surface; and comparing the first andsecond frictional forces.
 78. A method for conditioning a planarizingmedium used for planarizing a semiconductor substrate, the methodcomprising: engaging a conditioning body with the planarizing medium;moving at least one of the conditioning body and the planarizing mediumrelative to the other of the conditioning body and the planarizingmedium to remove material from the planarizing medium; and maintainingan approximately constant frictional force between the conditioning bodyand the planarizing medium by adjusting a relative velocity between theconditioning body and the planarizing medium.
 79. The method of claim 78wherein maintaining an approximately constant frictional force includesselecting a target frictional force, detecting a force between theconditioning body and the planarizing medium and adjusting the relativevelocity until the force is approximately equal to the target frictionalforce.
 80. The method of claim 79 wherein moving at least one of theconditioning body and the planarizing medium includes rotating theplanarizing medium relative to the conditioning body.
 81. The method ofclaim 79 wherein the conditioning body is coupled to a support memberfor supporting the conditioning body relative to the planarizing medium,further wherein detecting the force includes measuring a forcetransmitted to the support member by the conditioning body.
 82. Themethod of claim 81 wherein the support member includes a generallyupwardly extending portion coupled to the conditioning body and agenerally laterally extending portion pivotably coupled to the upwardlyextending portion, further wherein detecting the force includesdetecting a force between the upwardly extending portion and thelaterally extending portion with a force sensor.
 83. The method of claim81 wherein detecting the force includes detecting a deflection of thesupport member.
 84. The method of claim 81 wherein the support memberincludes a piston slidably received in a cylinder and detecting theforce includes detecting a movement of one of the piston and thecylinder relative to the other of the piston and the cylinder.